A bucket or bench seat installed in a vehicle such as a car, an aircraft, a ship and the like has a bottom and a backrest. The bottom is provided with a cushion (hereinafter referred to as a seat cushion), and the backrest is also provided with a seat cushion. Such a seat may be provided with a reclining mechanism and/or a mechanism for jumping up the bottom. In addition, the bottom and/or the backrest may be provided with a protuberant circumference for securely supporting a user.
The seat cushion comprises a surface material (or a cushion cover) and a cushion body covered with the surface material. The cushion body has a main part and a side part generally corresponding to a main part and a side part of the seat cushion.
The cushion body comprises a foamed body formed in a shape generally corresponding to a shape of the cushion body. The foamed body is soft to give a soft feeling. The cushion body further comprises a reinforcing material fixed to the foamed body. At least one of the main part and the side part of the cushion body is reinforced with the reinforcing material, and a deformation of the seat cushion is thereby restrained to support a user securely.
The foamed body is made of a foaming (or expandable) resin. In general, a foaming urethane resin is used as the foaming resin.
The foamed body is manufactured using a foaming apparatus comprising a molding device. The molding device comprises an upper mold having an inside corresponding to a shape of a back part of the cushion body and a lower mold having an inside corresponding to a shape of the main part and the side part of the cushion body. When the molding device is damped, an inner space corresponding to an outline of the cushion body is formed inside the molding device. An undiluted solution of a foaming resin is injected into the molding device and expands to form in a shape corresponding to the outline of the cushion body. Thereby, the foamed body is manufactured.
An undiluted solution of cold urethane foam is used as the undiluted solution of the foaming resin to be injected in the molding device. The undiluted solution of cold urethane foam produces gas. The gas is trapped inside the undiluted solution while the undiluted solution of cold urethane foam expands, so that bubbles of the gas are dispersed inside the expanded cold urethane foam. A part of gas produced by the undiluted solution is not trapped inside the expanded cold urethane foam and is exhausted through a vent hole(s) provided in the upper mold of the molding device until the inner space of the molding device is completely filled with the expanded cold urethane foam. Air initially presented inside the molding device is also exhausted through the vent hole(s). Then, the foamed body can be formed in a shape precisely corresponding to the inner space defined by the insides of the upper and lower molds.
The side part and the back part of the cushion body are reinforced by use of one or more reinforcing materials. A rigid or half-rigid plate is used as the reinforcing material. In order to provide a predetermined strength of reinforcement required for the cushion body, this reinforcing material is manufactured by densely binding urethane chips using a binder. Such a reinforcing material is positioned inside the molding device and an undiluted solution of a foaming resin is then injected in the molding device. While the undiluted solution expands to form the complete foamed body, the reinforcing material is fixed to a portion of the foamed body corresponding to the side part and/or the back part of the cushion body. (The undiluted solution of a foaming resin expands and impregnates into the reinforcing material so that a thin impregnation layer is formed in an overlapped portion of the foamed body and the reinforcing material. This thin impregnation layer merely serves to fix the reinforcing material to the foamed body. A portion outside of the plate-like rigid or half-rigid reinforcing material adjacent to the thin impregnation layer gives a predetermined strength of reinforcement required for the cushion body. The thin impregnation layer does not have any influences on the strength of reinforcement of the cushion body.)
Such a technique has been used as a technique for reinforcing the cushion body.
In such a prior art technique, it is disadvantageously difficult to deform the rigid or half-rigid plate used as the reinforcing material. If a portion of the cushion body to be reinforced is not precisely formed in a predetermined shape, the cushion body is not formed in a predetermined shape corresponding to an outline of the cushion body, and thus, it is necessary to cut a part of the reinforcing material before covering the cushion body with the surface material, and reinforcing the cushion body costs time and care.